1/4 cup diced shallots
1 large egg and 1 large egg yolk at room temperature
1 teaspoon lemon juice
2 teaspoons tarragon vinegar, divided
1 teaspoon Dijon mustard
1/2 teaspoon salt
1 cup vegetable oil
1/3 cup olive oil
Combine shallots, egg yolks, lemon juice, half the vinegar, all the mustard, and salt in a two cup measure or the wokbowl of a food processor or blender. Use an immersion blender to blend these ingredients for 15 seconds. Continuing to blend, add the vegetable oil in a thin, steady stream, increasing the flow after the first 1/2 cup is added. Continue with the olive oil.
If the mayonnaise gets very thick stop pouring and add the wine vinegar, otherwise add it after the oils have been added.
Refrigerate before and after use.
Yield: 1-1/2 cups
FIRST AID FOR BROKEN MAYONNAISE;
Warm a clean bowl with water and wipe dry. Whisk together a fresh, room temperature egg yolk with 1/2 teaspoon each lemon juice and mustard. Whisk in the separated sauce beginning with a thin stream and gradually increasing the flow after 1/2 cup has been added until the remaining sauce is combined.